48 • 



pine forests near Crow, Kaleigh County, I found that portions of the 

 trunks of some of the largest and finest looking white pine trees were 

 rendered worthless by the work of a large Buprestid larva, which had 

 entered the living wood from eggs deposited in slight wounds in the 

 bark. They mine in all directions through the heartwood, causing it 

 to become completely honeycombed, and finally resulting in the total 

 destruction of the heartwood from decay. Some full grown larvae 

 and fragments of an adult were found which were sufficient to identify 

 it as a very large species, probably closely allied to Chalcophora virgin- 

 iensis. The large woodpecker, Gampephilus principalis, appears to be 

 fond of the larvae, since in some living trees infested by this insect I 

 found large, square holes, some of them 3 by 5 inches at the surface 

 and 5 inches deep. 



Periodical cicada, Cicada septendecim. — The appearance of a 

 swarm of Brood XV over the larger part of the State in May and June, 

 1897, enabled me to obtain much additional information regarding the 

 distribution of this and other broods in the State. It appears from such 

 data as I have collected that we have at least eight broods in West 

 Virginia, namely: Broods XV, XVII, XX, XXI, XXII, Y, VIII, XI. 

 It was also found that the Cicada did far greater harm to old apple 

 trees than was heretofore supposed, owing to the wounds made by the 

 female in the terminal twig failing to heal, also to the fact that the 

 woolly aphis often inhabits the wounds and prevents them from healing, 

 both on young and old trees. 1 



Some evidence derived from the study of the phenological features 

 as related to the periodical Cicada, and certain widely distributed forest 

 trees, makes it seem probable that the dates of the periodical appear- 

 ance of the different swarms of the Cicada is governed by the same 

 phenological laws as those governing the periodical phenomena of 

 plants. Consequently, the first general appearance of the insect in any 

 given locality will probably correspond closely to the first general 

 appearance of leaves and flowers on certain plants, as with the first 

 flowers of the yellow or black locust, tulip tree, wild cherry, etc. 



I was also led to conclude from a study of phenological and tempera- 

 ture da f a that there is quite a uniform period of three to four days 

 difference in the periodical phenomena of insects and plants for each 

 degree of difference in the normal temperature of April to September, 

 inclusive, between two or more near by or distant places. 



This evidence led to a study of the temperature data of this and 

 adjoining States, and especially that relating to the Appalachian pro- 

 vince, in order to determine the rates of difference in normal tempera- 

 tures at different elevations and degrees of latitude. 



From the information thus obtained, I formulated rules and tables for 

 the approximate determination of the sum of heat, or normal tem- 

 perature of the season of growth and reproduction at any place in the 



Bulletin No. 50, West Virginia Experiment Station. 



